Pakistani police say they have arrested up to 40 people in connection with the killing of a Christian couple in Punjab province who were beaten , then pushed into a burning kiln after being accused of desecrating the Quran .

Local police officials said a mob from neighboring villages formed Tuesday after a local mullah declared the couple were guilty of blasphemy .

The mob allegedly marched to the couple 's home , broke down their door , dragged them outside , beat them and threw them into the brick kiln where they both worked .

The attack happened in the town of Kot Radha Kishan , about 60 kilometers -LRB- 37 miles -RRB- southwest of Lahore , the capital of Punjab . Police officials identified the woman as Shyman Bibi Urf Shamar , and her husband as Sajjad Nasir Zurjah Nazir Nasir .

The Human Rights Commission of Pakistan -LRB- HRCP -RRB- , which dispatched a team to the scene , said in a statement that the couple had three young children -- two sons and a daughter , and indicated the slain woman was pregnant .

`` HRCP is shocked and saddened beyond words by the callous murder of the couple and their unborn child , '' the group said .

According to the statement , the HRCP team `` did not come across any evidence of desecration of the Holy Quran . ''

Desecration of the Quran is punishable by death or life imprisonment under Pakistan 's anti-blasphemy law .

Human rights groups have long urged the country to repeal the law , arguing that it has led to discrimination , persecution and murder .

Woman takes blasphemy law to Pakistan 's highest court

It is often used to settle personal vendettas , rights groups say , and people accused of the committing the crime are frequently targeted by mob violence .

That , according to the HRCP , appeared to be the situation in Kot Radha Kishan , and that the incident stemmed with a dispute over money the kiln 's owners said the couple owed them .

An accusation that the couple had desecrated the Quran `` was spread to nearby villages and announcements -LSB- were -RSB- made through mosque loudspeakers , '' the HRCP said .

The mob that went to the kiln was estimated at around 500 people , the rights group said , citing local police .

The HRCP said its team learned that four policemen went to the kiln to demand that the couple be handed over for protection from the mob , but that the owners `` instructed their employees not to hand the couple over and the policemen were also beaten up . ''

The kiln 's owners were among those arrested , the rights group said , quoting police .

Pakistani newlyweds decapitated by bride 's family in honor killing

@highlight

Police : Mob attacked Christian couple Tuesday at the kiln where they worked

@highlight

They were beaten and thrown into the burning kiln

@highlight

Rights group calls it a `` callous murder , '' indicates woman was pregnant

@highlight

Blasphemy in Pakistan is punishable by death or life imprisonment